I'm still testing your Zoho Invoice software. I have ran into the following issue: 

I've set up a test customer. For which I have opened an invoice and paid the invoice with a credit note for the same customer. Now I want to delete the invoice but I can't. I get the message: " This invoice has credits applied to it. Hence, it cannot be deleted."

Next I went to the credit note to delete it but I can't delete it either. I get the message " Credits applied to invoice(s) or refunded cannot be deleted"

I would like to delete the invoice so that I can delete this test customer. Could you please help how I should go about this? 

Thanks, 

Revi